Post-tensioned concrete tanks are well known in the art. Such tanks have a system of vertical and horizontal tendons which are tensioned after the concrete sidewall of a tank is cured, so as to place the concrete in compression. In some cases horizontal tendons are within the wall, while in other cases external tension bands gird the wall. In any such structure, the tendons within the wall must be sheathed so they are free to slide relative to the concrete when they are placed in tension. In a typical post-tensioned concrete tank the vertical tendons are anchored within the wall near its base and have a stressing element at the top of the wall.
Concrete tank walls used in the storage of liquid slurries such as manure are subjected to large forces due to hydrostatic pressure from the input pump and ice which may form in the tank. Vertical forces are created that actually tend to lift a wall off its foundation, thus permitting the contents of the tank to seep under the bottom of the sidewall where its freezing and thawing can damage both the sidewall and the foundation.
Post-tensioned concrete tank sidewalls of the prior art are typically from eight inches to twelve inches thick, and need conventional metal reinforcing rods set in the concrete.